/Engine/Plugins/Runtime/GeometryProcessing/Source/DynamicMesh/Public/Parameterization/MeshPlanarSymmetry.h
the input Frame mirrored to the "positive" side (unchanged if it is already on the positive side)
[FFrame3d](API\Runtime\GeometryCore\FFrame3d_1) GetPositiveSideFrame ( [FFrame3d](API\Runtime\GeometryCore\FFrame3d_1) FromFrame ) const